Master cylinders of the type contemplated herein are provided with either a remote type reservoir wherein the oil supply is located at a remote location from the master cylinder or an integral type wherein the reservoir for the hydraulic fluid is a part of the master cylinder housing. Each of these styles has been individually designed for use in a particular environment. In both types the master cylinder generally included a housing or body having a longitudinal bore containing a piston assembly which is used to produce an increase in the hydraulic pressure in the bore in order to pressurize the brake lines for the brake assembly of a vehicle. The piston assembly is mounted in the bore of the master cylinder housing, and includes a number of seals which are continuously reciprocated in the bore in the housing. This continuous intermittent motion of the piston produces wear of the seals. If the seals fail or any other part of the master cylinder fails, the master cylinder has to be either rebuilt and/or replaced.
Each type of master cylinder formerly used a different type of piston assembly which increased the number of repair parts in inventory as well as down time when the master cylinder had to be replaced.